TY  - JOUR 
T1  - What do petrochemical workers, healthcare workers, and truck drivers have in common? Evaluation of sleep and alertness in Brazilian shiftworkers
JO  - Cadernos de Saúde Pública
A1  - Fischer, Frida Marina
SN  - 0102-311X
UL  - 10.1590/S0102-311X2004000600033
VL  - 20 
Y1  - 2004
PB  - Brasil 
ER  -